REPRODUCTION IN DOMESTIC ANIMALS, cilt.27, sa.3, ss.141-147, 1992 (SCI-Expanded)
In a total of 500 ewes (260 Merino, 120 Daglic, 120 Ramlic) of three sheep breeding farms in Turkey oestrus induction was performed by application of progestagen im-pregnated vaginal sponges+PMSG or of PGF2-alpha (given once or twice). 4 to 6 hours after oestrus detection by a teaser ram the ewes were inseminated cervically with frozen-thawed or fresh semen of rams of the same breeds. In all breeds the highest rate of oestrus induction (96.7 to 98.3%) was obtained by means of progestagen+PMSG. A single injection of PGF2-alpha provoced heat in 60%, while two injections with an interval of 9 days induced oestrus in 88.3% of the treated ewes. PGF-2-alpha had the best synchronizing effect (80.6 to 88.2%) at 48 hours after application. Regardless of the breed and the synchronization method, the non return rates 35 to 40 days after insemination were 21.4 to 41.9% and 55.6 to 84.2% for frozen-thawed and fresh semen resp. In all breeds the best non return results were observed after oestrus induction with progestagen+PMSG. With regard to induction and synchronization of oestrus breed dependent differences could not be statistically confirmed.